HIGH RESOLUTION ELECTRONIC ABSORPTION STUDIES OF 1,5-DIAZANAPHTHALENE.
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Date
1969
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Publisher
Ohio State University
Abstract
The vapor phase visible and ultraviolet absorption spectra of three diazanaphthalenes have received attention in the literature: cinnoline (1,2-), quinazoline (1,3-), and quinoxaline (1,4-). Furthermore, polarized absorption spectra of single and mixed crystals of phthalazine (2,3-diazanaphthalene) at $4.2^{\circ}K$ have been reported. In each case the weak, lowest energy absorption region is assigned to $\pi^{\ast} \leftarrow n$ transition(s), and the stronger bands at higher energies to $\pi^{\ast}\leftarrow \pi$ transitions. We wish to report vapor absorption measurements on 1,5-diazanaphthalene; the first case in which the nitrogen atoms are on adjacent rings in this family of molecules. High resolution absorption spectra were photographed using a 55,000 lines/inch grating for the region $2700{\AA}$ to $4000{\AA}$. The $\pi^{\ast}\leftarrow n$ system has an origin near $25,800 cm^{-1}$, with a strong prominent vibrational progression of $525 cm^{-1}$. The first $\pi^{\ast}\leftarrow \pi$ system has an origin at $32.874 cm^{-1}$ and consists of broad diffuse bands with up to six members of a prominent progression of $700 cm^{-1}$. A vibrational analysis will be presented.
Description
Author Institution: U. S. Army Missile Command, Redstone Arsenal